Clones are multiple connections to DALnet, often using specialized software to accomplish this. Clones are often used as tools with which to 'fill' a channel - i.e. to make it seem like it has lots of people in it.

Cases cloning and suspected fillers should be reported to an IRC Operator because they interfere with DALnet operations. You can find an IRC Operator and report the channel in which this is happening.

Instructions on how to find an IRC Operator are available at http://docs.dal.net/docs/findoper.html or you can join #OperHelp

You can also get more information about clones at http://docs.dal.net/docs/annoy.html#5